#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 2e5 + 5;

ll n, m;
int a[N];
ll sqrt2(ll n) {
  ll x = sqrt(n);
  if (x * x > n) x--;
  if ((x + 1) * (x + 1) <= n) x++;
  return x;
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n;
  cout << sqrt2(n / 2) + sqrt2(n / 4);
  return 0;
}